electric fan worth it?

jveik · #1 08-19-2006, 02:38 PM

im putting a 383 in my 73 chevy truck im restoring and i need to know if it is worth the price of putting electric fans to replace the one mounted on the water pump. also, if it isnt too much money, how do i go about setting that system up? do you just wire it into the fuseblock in a place that has power when the ignition is in the run position or do you have to get a fancy system that turns the fans on when the thermostat opens up. if it is really fancy and tempermental, i think ill just stick with the one that mounts on the water pump. oh by the way, how much more power should i expect from this motor if i switch out for the electric fans? Thanks ahead of time for any insights you may be able to give...

TEXAS-HOTROD · #2 08-19-2006, 03:04 PM

If you have an efficient (3 core/4 core) radiator and cool outside temps (it's been 100+ here lately) electric fans can work. A mechanical fan w/a Hayden fan clutch and the proper fan shroud will always cool better than any electric set-up.
For me it's easier to just wire the fans through a relay and into the ignition switch. Tie into the + post on back of the alternator to feed a fused circut to the fan relay, and then to the fan motors (using thick wire and a 30 amp fuse). The relay will need a ground source and a "keyed" ignition source (most relays have a wiring schematic stamped on the relay). When you turn on the key, the fans come on. There's less chance of fan failure that way.
It's more complex to wire in a temperature sensing control system, usually when the engine heats up and the fans come on, they usually stay on anyway.

jveik · #3 08-19-2006, 08:31 PM

ill have to look on my painless wiring harness to see if there is a circuit built in for electric fans or not...

jveik · #4 08-23-2006, 08:49 AM

well i looked in there and i noticed there is indeed a 20 amp circuit for an electric cooling fan. does anyone know how many cfm i will be needing to keep this crazy 383 from warping valves and stuff?

TEXAS-HOTROD · #5 08-23-2006, 10:31 PM

Don't power the fans through the fuse panel, things will melt.
Fans are controlled through a relay, powered from the battery and triggered by the ignition.
Cfm? The more the better. I like Flex-a-Lite's dual units.

jveik · #6 08-25-2006, 11:35 AM

so would i use the 20 amp electric fan circuit to power the relay, which would switch the juice on to the fans? should i use one of those couplings with a fuse inside to make sure if the fans short somehow that the fuse will blow and stop them from killing off the power? i actually had a problem kinda like that once, my battery slid over and contacted my fender and shorted out and the engine cut out in the middle of a crowded street lol!!! it seemed like it was tack welded to the fender almost lol

TEXAS-HOTROD · #7 08-25-2006, 09:18 PM

I'd say that you're on the right track.
I have a dual fan unit on one of my cars. I used 2 relays and 2 power supplies (2 fuses). If one fan motor fries, then there's a back-up fan. 2 is better than one, but 1 is better than none.
You could probably get by w/a 30 amp fuse to run a dual unit. I just went the extra step and wired mine in parallel.
My Biscayne has two sets of dual units (4 fans). I have it wired with 2 relays like the other car, each dual fan has its own 30 amp power feed. It works fine too.

I had a car come in the shop that the battery was welded to the hood. He installed a battery that was too tall. The battery posts melted to the bottom of the hood when he slammed it.

AlmostStock · #8 08-27-2006, 02:44 AM

You'll see very little HP difference by switching to an electric fan(s) because once the car is moving, (or racing) a clutched mechanical fan is no longer being turned by the engine. The fan is only needed at idle or slow speeds. The electric system will be more expensive, more complicated and more prone to failure.

tom3 · #9 08-27-2006, 01:46 PM

With that engine I'd go for a clutched belt drive fan with the correct shroud. Electric fans are great for many applications but you'll need some serious and dependable cooling for that. Not a big horsepower loss with a clutch fan that works right.

jveik · #10 08-28-2006, 01:26 PM

yeah i was looking into that whole thing and i noticed that there are manufacturers that make water pump-mounted fans with flexible blades that claim they flex at high rpm to let the motor not loose much power. Is this all a bunch of b.s. that isnt needed due to the existence of the fan clutch, or is it worth looking into?

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